Putri, V. N. E., Y. Yudiana, D. Z. Sidik, E. Nugraha, and T. Jatmiko. “The OPT (Optimum Performance Training) Method for 12 Weeks Increases Strength and Power of Female Athletes from the Indonesian National Beach Volleyball Team”. Jurnal SPORTIF : Jurnal Penelitian Pembelajaran, vol. 10, no. 3, Dec. 2024, pp. 405-19, doi:10.29407/js_unpgri.v10i3.23200.